1. Field of the Invention
The present invention relates to downhole injection apparatus for well treatment, and more particularly, to a fluid control valve for use with an injection packer and circulating valve. The fluid control valve designed to prevent loss of treating fluids to well formations when the packer is being moved from one position to another.
2. Description of the Prior Art
Testing and treating of well formations is, of course, well known. One apparatus useful for these purposes is the Halliburton RTTS (Retrievable Test-Treat-Squeeze) packer which is adaptable for performing multiple operations on one or more zones with one trip into the well bore. After treating one zone, the RTTS packer can be moved to other positions in the hole, where other zones can be similarly treated.
Another packer useful for treating small portions of a well formation is the Halliburton PPI (Pin Point Injection) packer which may be used to straddle sections of perforated casing a small amount at a time. The entire formation can be evenly broken down before running the main treatment because the operator can move up the casing with a series of small injections. That is, the packer may be set and used to treat a small portion of the formation and then moved to treat additional small portions.
Typically, with packers such as the RTTS packer and the PPI packer, a Halliburton RTTS circulating valve may be used for circulating fluid above the set packer and as a bypass as the tool is run into the hole. The valve is automatically locked in a closed position when the packer is set.
Tool strings using the RTTS packer or PPI packer with the RTTS circulating valve have worked well. However, in low fluid formations, it is possible that the well treating fluids may be lost to the formation when the packer is being moved. That is, some well formations will not hold a fluid column because of a low pressure zone, and the well treatment fluids may simply flow out of the tool into the well formation and be irrevocably lost. This results in lost time and increased treatment costs, both of which are undesirable.
The present invention solves these problems by providing a fluid control valve which may be used with injection packer tools such as those described above and which is designed to hold the well treating fluids above the circulating valve and thus maintain a column of fluid in the work string when the packer is moved from one setting position to another.